Saenai Ore no Tensei Saki ga Mob Reijou!?

Original Webtoon
https://mechacomic.jp/books/189712
Kei, a typical high school boy, finds himself reincarnated into the world of an otome game he once played at his sister's request! However, he has inexplicably become Kate, a background character. Despite being a minor character, the handsome main characters approach Kate as if she were the heroine! Initially, Kate is determined to conquer the game, but she realizes that completing the game means marrying one of the male characters. To avoid the marriage route at all costs, Kate decides to support the romances between the main characters and the villainess. However, the story starts to veer off from the original game plot... With the help of her childhood friend Edgar, who is also a background character but too handsome to ignore, Kate navigates this unexpected turn of events!